1. Field of the Invention
This invention relates to a surgical file instrument that is used in a surgical procedure for removing bone from a patient. More particularly, the invention relates to the file and guide/shield portion for cutting, removing, grinding, shaping and sculpturing bone and to the configuration of the file, and guide/shield to assure that the reciprocating file remains centered when being used and precludes any wobbling motion.
2. Description of Related Art
There are a number of surgical file instruments that are commercially available and as one skilled in this art appreciates, it is abundantly important that the blade of the file of the surgical file instrument when in operation remains centered and does not vacillate from that plane. In other words, the file must remain within its operating plane and stay along the center line for precision bone removal. Moreover, the file blade must be shielded so that the portion of the anatomy that isn't being worked on is not inadvertently cut or bruised. The file must be dimensioned so that it can be used in very tight and close areas in the body that are typically difficult to get to in order to perform precision surgical operations.
There are commercially available surgical file instruments that have a sundry of applications that may be used by a surgeon for the treatment of certain types of pathology. For example, U.S. Pat. No. 7,390,330 ('330) granted to Harp on Jun. 24, 2008 essentially relates to a surgical file instrument that is similar to the surgical file instrument described in the present patent application, however, the invention described in this patent application patentably distinguishes over the surgical file disclosed in the U.S. Pat. No. 7,390,330 ('330), supra. The '330 patent, supra, discloses a shielded reciprocating surgical file system and allows a user to navigate the file into hard to access parts of the patient's body. It also describes a transmission mechanism that converts rotary motion from a motor into reciprocating motion, pump mechanism and an irrigation system that supplies fluid to the surgical site.
In one embodiment in the '330 patent, for example, the cutting blade is shielded on five sides to provide a shielded surgical file. The file can be dimensioned so that it extends generally straight, curved, angled or bent along the longitudinal axis. The file needs to be compatible to fit into the human or mammalian anatomy portions. Its thickness must be thin so that it fits into small spaces such as between a nerve and the foramen opening that it is passing through and the cutting blade can be shaped or contoured. The present invention is capable of performing these types of operation with a less complicated file. In other words, the present invention is characterized as being relatively simple to, make, less costly and yet, it is efficacious.
To obtain the reciprocal motion from the rotary motion, the structure disclosed in the '330 patent, supra, utilizes a torus transmission device which may include an integral shaft or a rigidly connected shaft. The torus drive and drive shaft are rotatable about a central rotation axis and has a generally circular or curvilinear cam portion with the torus central axes being at an offset angle. The variable thickness of the torus cam surface produces a hybrid dual or twin torus. Similar to what is disclosed in the '330 patent, supra, the present invention has utility for many medical procedures that are typically the concern in neurosurgery, orthopedic surgery and plastic surgery, amongst others. For example in neurosurgery, the neruroforamen may need enlargement and the file can be instrumental in removing rigid bony vertebral structure to allow the nerve roots to pass there through. In orthopedic surgery the knee may require sculpturing. And, in plastic surgery bone and tissue sculpturing may be required for nose reshaping and rhinoplasty.
It is imperative in this type of surgical file instrument that the file blade doesn't wobble or get out of line while being used. To this end we have found that by contouring the central portion of the guide/shield with a dimple having an apex bearing against the underside of the blade and providing a unique configuration to the side portions of the dimple extending from the apex in which the file blade is in sliding relationship, the surgical file and blade remain in a fixed plane during its reciprocating condition.
While this invention provides the configuration for assuring that the file remains in-line, this feature is in combination with a surgical file instrument that includes a specific motion converter having a planetary gear system and a cam with a thrust control as well as having a file assembly that includes an elongated outer tube casing, a file having an elongated angular shaft portion having a blade on the distal end and a tang on the proximal end and an encapsulated elongated cylindrical solid tube of plastic material. The solid tube is formed with an elongated generally “infinity symbol” shaped aperture and lumens extending in a longitudinal direction. The “infinity shaped” lumen serves as a passageway for the shaft of the surgical file and the other lumens serve to define passageways to access the surgical site.